As I was working in an article today I found two issues that need attention.
1) When you see in parallel the original and the translated text, the length is not comparable, so for long articles the two are not aligned, and original sentence and translation can be two pages appart. I think the text should be aligned, at least in the paragraph level, by introducing blank lines.
2) As I was working on a short article, there were 12 sentences to be translated, but I couldn't locate the 12th. As it turnes out, it was a pair of quotation marks " " that were sitting in some blank space. So I wanted to leave a comment for the next translator or the duolingo staf, but there is no option to write comments, only to report abuse/copyright violations. I think we should be allowed to leave comments for articles in a similar maner like for sentences, and this should appear in a different tab in the discussion section.